Modern mattresses generally include an inner construction and a mattress sack that completely covers the inner construction. The sack is secured to the inner construction by means of a flange which is connected to the inner construction using hog rings or the like.
The ticking material of a mattress sack may be of many types, such as flat or quilted, and the sack generally includes identical top and bottom panels and a side panel, joining the top and bottom panels. The top and bottom panel may be sewn directly to the side panel, joined with boarder tape, or attached with a gusset.
To reduce manufacturing cost, attempts have been made to automatically attach the side panel to the top panel. Typically, these attempts have held the inner construction stationary on a table and have positioned the mattress sack over the inner construction. A self-propelled sewing machine then joins the side and top panel, by boarder tape for example, by moving around the table via a track mechanism. Many modifications to this basic structure have been made and will not be repeated here for the sake of brevity.
More recently, the basic principle of propelling the sewing machine around the mattress has been reversed: now, the mattress is moved, not the sewing machine. For example, U.S. Pat. No. 4,043,282 describes a mattress tape edge closing machine, in which the mattress and cover are lifted at an angle with respect to a stationary machine. The mattress is then moved past the machine. In addition, U.S. Pat. No. 4,838,186 describes a sewing machine, including presser elements rotatably supported about a vertical axis to allow rotation of the mattress sack. Furthermore, U.S. Pat. No. 4,958,579 describes a device for sewing the edges of a mattress cover on an inner construction, including a swingable arm for rotating the mattress construction.
Some of these machines are cumbersome because they operate on the entire mattress construction. Others have difficulty maintaining high quality "sizing", a necessity in the mattress field. "Sizing" is a term known in the art and is used to refer to the uniformity of a mattress's stitching and dimensions, and more generally to its appearance.
Those skilled in the art will appreciate that a low cost and reliable machine for forming mattress sacks is needed.
Therefore, it is an object of the invention to provide a low cost machine for manipulating flexible fabrics, yet maintaining high quality sizing.
It is a further object of the invention to provide a method and apparatus for manipulating mattress sacks and other flexible fabrics, such that the feeding of the material to the apparatus is automatically monitored and corrected to insure high quality sizing.
It is yet another object of the present invention to prepare the panel to ensure that panel filling does not protrude from the ticking layer.